// Created on savesnippets.com · https://savesnippets.com/BEIDQuXLoyRUTv
function createWeakCache() {
  const cache   = new Map();
  const registry = new FinalizationRegistry((key) => cache.delete(key));

  return {
    set(key, value) {
      cache.set(key, new WeakRef(value));
      registry.register(value, key);
    },
    get(key) {
      return cache.get(key)?.deref() ?? null;
    },
    has(key) {
      return this.get(key) !== null;
    },
  };
}

// Usage
const imgCache = createWeakCache();
const img = new Image();
img.src = '/hero.jpg';
imgCache.set('hero', img);
console.log(imgCache.get('hero')); // Image element (while alive)